Cylinder ridge grinder



Jan, 21, w41. c..4 soLBRlG 2,229,314

' CYLINDER RIDGE GRINDER Filed Feb. l2, 1940 2 Sheets-Sheet l 11111.21,1941. SOLBRIG 2,229,314

CYLINDER RIDGE GRINDER Filed Feb. 12, 1940 2 sheets-sheet 2 byu-en orGusiaz/ .Sblbr Patented Jan. 21, 1941 UNITED STATES CYLINDER RIDGEGRINDER Gustav Solbrig, Cedar Rapids, Iowa, assigner of forty-eight percent to William H. Dutton,

Minneapolis, Minn.

Application February 12, 1940, Serial No. 318,500

6 Claims.

My present invention relates to an improved tool for grinding or cuttingdown the annular ridges at the tops of engine cylinders, and may be'hereinafter referred to as a cylinder ridge grinder.

In various types .of engines and pumps employing piston equippedcylinders, the greatest wear on cylinders is produced by the pistonrings, which latter are under resilient tension to expand against thecylinder. Since the piston rings are located below the top of the pistonand the piston ring travel on the cylinder terminates somewhat short ofthe top of the cylinder, the cylinder becomes enlarged by piston ringwear throughout the portion traversed by the rings and this leaves anannular ridge above the piston ring travelled portion of the cylinder.When the pistons are removed from the cylinders for the purpose ofreplacing the piston rings, it be- 20 comes desirable, and in fact inmany cases necessary, to cut down this annular ridge near the top ofthel cylinder to a diameter equalling that of the ring worn portion ofthe cylinder therebelow.

An important object of the present invention is the provision of a verysimple and inexpensive, but highly eflicient tool by which the ridgesleft in the top of cylinders as a result of ring wear 3o therebelow canbe quickly and accurately cut down to the diameter of the ring wornportion of the cylinder.

Another important object of the invention is the provisionof a tool ofthe kind described which is adapted to be power operated vfrom aportable hand operated unit such as a conventional motor driven drilldriving unit. y

Another object of the invention is. the provision of a tool of the classdescribed that is adaptable without adjustment to operate with equalefficiency on cylinders of different diameter. f

Another important objective of the invention is the provision in a toolof the class described employing a plurality of abrasive carrying shoesthat exert pressure on the cylindrical surface being ground as a resultof centrifugal action, and wherein the shoes are provided with shouldersthat overlap the top of the cylinders and ,50 denitely limit downwardmovement of the abrasive surfaces of the shoes to a position whereintheir outer ends are above the tops of the cylinders.

Another important objective of the invention is 55 the provision in atool of the class described in- (Cl. 51--184.1) y

corporating centrifugally movable segmental grinding shoes that arefaced with removablev strips of flexible abrasive such as emery cloth,of an improved simple and extremely efiicient anchoring medium for suchabrasive strips.

'Ihe above, and other and highly important advantages of the inventionwill be made apparent from the` following, specification and claimstogether` with the appended drawings. In the accompanying drawings,likecharacters indicate like parts throughout the several views.

Referring to the drawings:

Fig. 1 is a View in side elevation .of one form of the tool.illustrating the same in an operative position in a cylinder that isshown in'section;

Fig. 2 is a view taken on the line 2 2 of Fig. 1, andshowing the tool ofFig. 1 in bottom plan;

Fig. 3 is a detail sectional view taken on the line 3 3 of Fig. 2; Y 20Fig. 4 is a perspective view of one of the abrasive strips for the shoesof the forms of the tool herein illustrated;

Fig. 5 is a view corresponding to Fig. 2vbut illustrating a slightmodification of the tool; and 25 Fig. 6 is a view corresponding to Figs.2 and 5,

but illustrating still another form of the tool.

With reference first to Figs. 1 to 4 inclusive, an engine cylinder isindicated `as an entirety by l. This cylinder 1 has at its upper end a30 smaller diameter portion forming an inwardly projecting ridge 8,which ridge is left in the cylinder las a result of piston ring weartherebelow.

The tool of Figs. l` to 3 includes a disc-like head Shaving an axiallyoutwardly, extended shank or spindle I8. Pivo-tally mounted to theunderside or face of the head!! at II area pair of shoes each indicated'as an entirety by I2. The shoes I2 each comprise a flat flange I3having a segmental outer edge, and a depending seg- 40 mental abrasivecarrying flange I4, which latter is also segmental, and is spacedradially inwardly from the outer edge of its respective ilat upperflange I3. The at upper flanges I3 of the shoes are pivotally anchoredto-the disc-like head 9 45 at II preferably by rivets Whichhold'the samesnugly against'the under face of the head, but

, permit free pivotal movements under centrifugal action. The radius ofthe are of each segmental flange I4 of the shoes I2 preferably'should bemade no greater than that of the smallest cylinder to be operated on.

Of course, the pivoted shoes I2 will-tend'to move Aoutwardly under theaction of centrifugal force when the device is rotated in a cylinder,

but this pivotal action of the shoes will be held Within predeterminedlimits by engagement of shoe carried bolts or the like I 5 with the endsof arcuate slots I6 in the rotary head 9.

These bolts I5 will further aid in holding the shoe flanges I3 snuglyagainst the under side of the head 9. The flanges I3 and I4 of the shoesI2 may be assumed to be integrally formed of cast iron or steel, butmay, of course, otherwise -be made or formed of lother materials.

The outer face of each of the segmental shoe anges I4 is faced with astrip of flexible abrasive material such as emery cloth or sand paper;emery cloth being preferred. These facing strips of emery cloth or thelike, and which are indicated by I1, are preferably the same depth asthe flanges I4, but are longer than said anges and have their endsdoubled around the ends of the segmental flanges "I4, and detachablyclamped in place by spring clamping devices forming an important phaseof the instant invention.

These clamping devices each comprise a normally straight and tightlycoiled spring I8 terminating at its opposite ends in an out-turned loop|19 serving as a -nger grip. The normally straight tightly coiledsprings I8 are yieldingly bent in two to conform substantially to thearcuate curvature of the inner faces of the shoe flanges I4, and aremaintained in this shape normally by engagement with headed anchoringstuds 20, which latter are shown as being in the nature of nut equippedbolts. The head acting nuts of the studs 20 overlap the spring anchorsI8 cross sectionally, and thereby retain the same against accidentaldisplacement. Of course, the spring anchors I8, due to their resilientnature, and the fact that they are tightly coiled when straight, tend tostraighten out and thereby exert a relatively very high degree ofyielding pressure against the opposite end portions of the anges I4. Toclamp the doubled back ends of the abrasive strips I'l in place, theends of the spring anchors I8 are bent back as shown by dotted lines inFig. 2, while the free ends of the abrasive strips are'doubled intoengagement with the backs of the anges I4 after which the ends of thespring anchors are released and come into tight clamping engagement withthe ends of fthe strips. Retraction of the ends of the spring anchorsaway from the shoe anges is most readily accomplished by compressingopposite loop ends I9 thereof between the thumb and forenger of onehand.

Operation of device of Figs. 1 to 3 inclusive Preparatory to thegrinding operation, the abrasive equipped shoe anges I4 are dropped intoa ridged cylinder to the maximum extent permitted by engagement of theradial projecting edge portions of flanges I3 with the top of thecylinder. For the purpose of rotating the tool, the axially disposedstem or shank Ill of the head 9 will usually be clamped in the chuck 2|of a portable power drill unit or the like, not shown. At any rate, itis contemplated that the power driven rotating unit will be of theportable type, which will be held in the operators hands. When the motorof the power unit is turned on, the tool will be rotated at relativelyhigh speed and the shoes will be thrown outwardly into grindingengagement with the ridged portion of the cylinder by centrifugal force.Usually during the grinding operation, the operator will raise the toolslightly so that the projecting edge of flanges I3 will be out offriotional engagement with the top of .the cylinder, substantially asshown in Fig. 1.

Due to the low cost of the abrasive strips and the easy replacement, astock of such strips with diiferent degrees of abrasive quality may bekept on hand at all times, and new strips of the proper abrasivequalities `for any particular job can be applied for that particularjob.

The device of Fig. 5 is like that of Figs. 1 and 2, in all respectsexcept that, whereas the two shoes I2 of Figs. 1 and 2 are pivoted atopposite ends, the two shoes of Fig. 5 are pivoted at like ends. In thisrespect, it may ybe said that the arrangement of Fig. 5 has someadvantage `over the device of Figs. 1 and 2 in that a better balancewill be maintained on a rotation and the extent o-f centrifugal actionon both shoes will `be the same. The several elements of Fig. 5 areindicated by the same characters as are assigned to correspondingelements in Figs. 1 to 3 inclusive, plus the exponent a.

T'he device of Fig. 6 differs from those of Figs. 1 to 4 inclusive onlyin the m-anner of mounting the shoes on the rotary head, and all partsin Fig. 6, which correspond to parts in Figs. 1 to 3 inclusive will beindicated by like parts plus the exponent b. The shoes in Fig. 6, inplace of being pivotally anchored to the disc-like head of the tool, areanchored to the disc-like head 9b for limited radial movements throughthe medium `of nut and head equipped bolts 22 that work in laterallyspaced slots 23 in the head 9, and are anchored fast in the flanges I3bof the shoes |217.

What I claim is:

1. In a cylinder ridge grinding tool, a rotary head having asubstantially circular flat face, an opposed pair of shoes workingagainst the at face of the head and anchored thereto for limitedmovements toward and from the axis thereof, each of said shoescomprising a radially extended at anchoring iiange lying .against thesaid face of the head and an axially extended segmental flangeprojecting from the radially extended flat flange, a primarily iiatstrip of flexible abrasive material covering the segmental outer surfaceof each axially extended shoe flange and having its free ends turnedover the ends of said segmental anges and doubled back over the endportions of the inner segmental faces thereof, and means for detachablyanchoring the folded back ends of the abrasive strips to theirrespective flanges, the anchoring means for each shoe comprising anormally straight spring 4anchored to the shoe at its longitudinallyintermediate portion in such close relation to the concave inner surfaceof the segmental Iiange thereof that it will be made to conform normallyto the concave contour of said segmental flange and the free endsthereof will be yieldingly pressed toward the segmental ange, saidspring being of such length that the free end portions thereof willoverlap the folded back ends of the abrasive strip and detachably anchorthe same in position.

2. The structure defined in claim 1 in which the said anchoring springsare tightly coiled wire springs.

3. The structure defined in claim 1 in which the said `anchoring springsare tightly coiled Wire springs and in which the ends of said anchoringsprings `are provided with outwardly turned finger engaging loops'.

4. In a grinding tool of the kind described, a rotary head, a grindingshoe mounted on said head for movements toward and from the axisthereof, said shoe having a depending abrasive outer surface and a stopange overlying said abrasive surface and projecting radially beyond thesame, and serving as the means for limiting the movement of said toolaxially into a cylinder or the like.

5. The structure dened in claim 4 in further combination with yieldingmeans connecting said shoe to said head and exerting force to press thesame outward.

6. The structure dened in claim 4 in which there is a plurality of saidshoes circumferentially spaced and independently `connecfbed to saidhead. 5

GUSTAV SOLBRIG.

